Movement characteristics and hyperactivation of human sperm on different epithelial cell monolayers

Endometriosis affects sperm–endosalpingeal interactions

BACKGROUND

The interaction between spermatozoa and the epithelium of the isthmic region of the uterine tube is thought to be an important part of the mechanisms of sperm transport to the site of fertilization and in preparing them for fertilization. However, it is unclear whether a dysfunction of this mechanism may contribute to subfertility in some individuals.

METHODS

The sperm-binding characteristics of the epithelium from the uterine tubes of three groups of women were examined: (i) eight with pelvic endometriosis (not involving the uterine tubes); (ii) five women who had been receiving zoladex injections to control their symptoms; and (iii) as controls 10 women undergoing an elective procedure for benign gynaecological problems but with no other pathology of the reproductive tract.

RESULTS

Significantly more spermatozoa bound per unit area to the ampullary epithelium of the uterine tubes taken from women with a previous diagnosis of endometriosis.

CONCLUSIONS

These findings suggest that the characteristics of sperm binding to tubal epithelium may be disrupted in women with a gynaecological pathology such as endometriosis. It is suggested that this may have the potential to interfere with the availability of freely motile spermatozoa, of the appropriate physiological status, to take part in fertilization. This may be a newly described mechanism by which endometriosis can cause infertility.

Importance of sperm-to-epithelial cell contact for the capacitation of human spermatozoa in fallopian tube epithelial cell cocultures

OBJECTIVE

To investigate the mechanisms involved in the stimulatory effect of fallopian tube epithelial cell coculture on sperm movement characteristics.

DESIGN

Human spermatozoa were cultured with human fallopian tube epithelial cell monolayers. A microporous membrane was used to prevent sperm-to-epithelial cell contact. Sperm movement characteristics were measured at 4 and 24 hours.

SETTING

University hospital and fertility center.

PATIENT(S)

Voluntary donors.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Movement characteristics of human spermatozoa.

RESULT(S)

Fallopian tube epithelial cell coculture increased sperm motility, curvilinear velocity, amplitude of lateral head displacement, and hyperactivated motility, mainly at 24 hours, compared with controls. These stimulatory effects were inhibited when a microporous membrane prevented cell-to-cell contact between sperm and fallopian tube epithelial cells.

CONCLUSION(S)

Physical contact between sperm and epithelial cells in coculture systems seems to be the main factor in stimulating sperm movement characteristics, and this could be the main mechanism of in vivo sperm capacitation.

In vitro interactions of cryopreserved stallion spermatozoa and oviduct (uterine tube) epithelial cells or their secretory products

Formation of a spermatozoa ('sperm') reservoir in the mare is thought to occur through lectin-mediated sperm attachment to the oviductal epithelium. Once attached, prefertilization sperm survival is supported by oviductal factors. Cryopreservation of stallion sperm decreases the number of sperm attaching to oviduct epithelial cells (OEC) and the length of time these sperm survive. Quantification of in vitro interactions between sperm and OEC in a co-culture system may provide an assay for functional integrity of cryopreserved or fresh sperm samples. Additionally, superior additives for in vitro handling of stallion sperm may be isolated from OEC secretory products. Experiment 1 compared first service conception (FSC) rates resulting from the use of cryopreserved sperm of seven stallions, with sperm function in co-culture such as attachment to OEC and subsequent survival time. Stallions were grouped by cumulative FSC rates observed over three seasons as having average (44 +/- 3%) or high (65 +/- 2%) fertility over a total of 217 first services (31 +/- 9 per stallion). Samples from stallions in the high fertility group had more (P = 0.04) sperm attached to OEC and longer subsequent sperm survival in co-culture (P = 0.05) as compared with those from the average fertility group. FSC rates correlated with numbers of sperm attaching to OEC and their survival time in co-culture (r > or = 0.71). In Experiment 2, the function of cryopreserved stallion sperm was evaluated in culture with OEC secretory products from three different sources. After 5 h of culture, sperm incubated with medium conditioned by bovine OEC which had been 'bioactivated' (e.g. previously exposed to sperm in culture) were found to be more (P < or = 0.05) motile and capacitated as compared to sperm in basal TALP medium alone. Sperm in this conditioned medium also survived longer (P = 0.05; 27 +/- 5 h vs. 17 +/- 4 h) than did those in control medium.

Induction of dog sperm capacitation by oviductal fluid

Four estrous beagles were inseminated with 1 x 10(8) sperm into both the right and left uterine horns, and the uterine horn and oviduct on one side were removed under anesthesia after 7 hr and 24 hr, respectively. The lumen of the uterine horns and oviducts was flushed with canine capacitation medium (CCM), and movement of the sperm in CCM was assessed by phase-contrast microscopy. In a second experiment, ejaculated sperm obtained from 5 normal beagles was incubated in CCM supplemented with oviductal flush fluid (OF-CCM) at 38 degrees C with 5% CO2 in air. Motility of sperm, and percentages of hyperactivated sperm (%HA) and acrosome-reacted sperm (%AR) among freely swimming (FS) sperm were investigated until 24 hr after the start of incubation. After 7 hr of incubation the sperm was coincubated with canine oocytes in OF-CCM for 2 hr, and the number of zona pellucida-binding (zona-binding) sperm was then counted. The %HA among the sperm in the oviductal flush fluid both 7 hr (mean +/- S.E.; 15.0 +/- 2.4%) and 24 hr (77.5 +/- 5.2%) after intrauterine insemination were significantly higher than in the uterine flush fluid (P < 0.05, 0.01, respectively). The motility and %HA among FS-sperm in OF-CCM were higher than in the control medium without oviductal fluid. However, there was no difference in the %AR between OF-CCM and control medium. The number of zona-binding sperm in OF-CCM (8 +/- 1) was significantly greater than in control medium (5 +/- 1) (P < 0.05). These results suggest that oviductal fluid in the estrous bitch maintains sperm motility and induces sperm capacitation.

Follicular fluid and human granulosa cell cultures: influence on sperm kinetic parameters, hyperactivation, and acrosome reaction

OBJECTIVE

To evaluate the influence of human granulosa cell (GC) cultures and follicular fluid (FF) on sperm kinetic parameters, hyperactivation, and the acrosome reaction compared with the influence of human tubal fluid (HTF) and Ham's F-10 medium.

DESIGN

Sperm kinetic parameters, hyperactivation, and the acrosome reaction were evaluated after 6 hours of incubation in HTF, Ham's F-10 medium, FF, and GC cultures.

SETTING

Infertility and In Vitro Fertilization Centre, Reproductive Endocrinology Unit, Institute of Obstetrics and Gynaecology.

PATIENT(S)

Sixteen normal semen samples.

INTERVENTION(S)

Sperm kinetic parameters and hyperactivation were analyzed using an automated videomicrography system, the acrosome reaction was performed using a triple-stain technique, and progesterone and 17OH-progesterone levels were measured with the use of commercially available kits.

MAIN OUTCOME MEASURE(S)

Sperm kinetic parameters, hyperactivation, acrosome reaction.

RESULT(S)

The percentage of motile sperm, the mean curvilinear velocity, and the mean of the maximum amplitude of lateral head movement were increased significantly after 6 hours of incubation in FF or GC cultures compared with incubation in HTF or Ham's F-10 medium, whereas the mean linearity was decreased significantly. Follicular fluid and GC cultures significantly increased hyperactivation and the acrosome reaction compared with the values obtained using HTF and Ham's F-10 medium. Progesterone and 17OH-progesterone levels were increased significantly after incubation in FF and GC cultures compared with HTF and Ham's F-10 medium.

CONCLUSION(S)

Follicular fluid and GC cultures increase sperm motility parameters, hyperactivation, and the acrosome reaction. This effect may be related to GC detoxification of the microenvironement or GC secretion of peptides, glycoproteins, growth factors (insulin-like growth factors 1 and 2), or steroids (progesterone and 17OH-progesterone).

Coculture of human spermatozoa with reproductive tract cell monolayers can enhance sperm functions better than coculture with Vero cell monolayers

PURPOSE

In order to develop a better system for support of human sperm function in vitro, we conducted studies to evaluate whether reproductive tract cells are better than non-reproductive tract cells as an adjunt in that regard.

METHODS

Human spermatozoa were cocultured with Vero cells, with human oviduct cells and endometrial cells, and without cells (control) for either 1, 4, or 24 hr. Sperm motility was then analyzed with a computer-aided sperm analyzer (CASA-Hamiliton Thron, HTM IVOS Motility Analyzer). Aliquots of spermatozoa incubated for 24 hr were also stained with Hoechst 33258 and FITC-PNA to evaluate the status of acrosome in live cells.

RESULTS

Significant differences (P < 0.05) between the oviduct cell and the control groups after 24 hr were evident in the curvilinear velocity (VCL) (81.4 +/- 13.4 vs 60.0 +/- 14.1 microns/sec) and amplitude of lateral head displacement (ALH) (5.2 +/- 0.6 vs 4.1 +/- 0.5 microns). The incidence of acrosome reaction of live sperm was significantly higher in the endometrial cell group than in the controls (25.4 +/- 9.9 vs 6.6 +/- 2.4%; P < 0.001).

CONCLUSIONS

Coculture with human reproductive tract cells seems to improve some functional parameters of human spermatozoa. Coincubation with such cell lines, especially oviduct cells, might be a feasible approach to optimization of human spermatozoa for assisted fertilization using subfertile or frozen-thawed samples. We think coincubating human spermatozoa with a human reproductive tract cell line, especially oviduct cells, might be a feasible approach in preparing human spermatozoa for assisted fertilizatioin in subfertile and frozen-thawed semen samples.

Effects of progesterone on human spermatozoa prepared for in-vitro fertilization

Progesterone has been tested in vitro with human spermatozoa to verify its physiological effects and its possible therapeutic use in cases of male infertility. Progesterone induced a rapid, dose-dependent influx of calcium in capacitated and non-capacitated spermatozoa with a half-maximally effective dose of 30 nM. The agonist, 19-nortestosterone, was much less potent that progesterone itself. Progesterone-induced calcium influx was not inhibited by a similar concentration (0.1 microgram/ml) of RU 486, a classical progesterone antagonist. The increase in intracytoplasmic calcium levels was unable to induce the acrosome reaction (AR) even after incubation for 5 h, when this was evaluated by double staining, using a monoclonal antibody GB24 raised against the inner acrosome membrane and ethidium homodimer as a vital probe. However, after incubation for 5 h, progesterone was able to enhance the tyrosine phosphorylation of a 95 kD sperm protein, which is phosphorylated progressively during capacitation in well-defined culture media. Incubation of spermatozoa with 1 or 10 micrograms/ml progesterone for 3 or 30 min did not induce major modifications of hyperactivated movement when analysed by computer-assisted semen analysis. Progesterone secreted by cumulus cells may physiologically increase sperm intracytoplasmic free calcium during capacitation. This priming effect may facilitate the acrosome reaction, induced by binding to the zona pellucida, without enhancing spontaneous acrosome reaction prematurely. It therefore seems useful to propose progesterone as a means of accelerating capacitation during in vitro fertilization in cases of male infertility.

Epithelial cell coculture and the induction of sperm capacitation

OBJECTIVE

To investigate the influence of cultured human oviductal epithelial cells on the movement characteristics of human spermatozoa.

DESIGN

Human spermatozoa were cultured with monolayers of human epithelial or Vero cells or conditioned media derived from these cell types. The viability and movement characteristics of the cells was subsequently analyzed at 4, 24, and 48 hours.

SETTING

University hospital and Medical Research Council laboratories.

PATIENTS, PARTICIPANTS

Volunteer donors.

MAIN OUTCOME MEASURES

Movement characteristics of human spermatozoa.

RESULTS

The presence of both Vero and oviductal epithelial cells, but not conditioned media, had a general promoting effect on sperm survival, significantly enhancing sperm viability and motility for up to 48 hours of culture. In addition, the presence of oviductal epithelial cells had a specific, significant stimulatory effect on sperm capacitation, enhancing the incidence of hyperactivated motility after 4, 24, and 48 hours of culture. Significantly, this effect was not observed with cocultures containing Vero cells.

CONCLUSIONS

The coincubation of human spermatozoa with human oviductal epithelial cells provides a convenient system for the induction and analysis of sperm capacitation.

Movement characteristics of human spermatozoa collected from different layers of a discontinuous Percoll gradient

In order to evaluate the functional state of human spermatozoa separated on discontinuous Percoll gradient, sperm provided by 15 healthy volunteers were recovered from different layers (60, 70, 80, 90, 100%) of the gradient, then submitted to a complete analysis of sperm movement characteristics. This one was performed using a computer assisted system (Cellsoft, Cryo Resources, Ltd., NY, USA). In all fractions sperm motility was highly maintained during 24 h and all movement characteristics, with the exception of ALH, were different from that observed in seminal plasma. Curvilinear velocity (VCL), linearity (LIN), and percentage of hyper-activated sperm (HA) increased in relation to the Percoll concentration. Nevertheless there was no dramatic difference, concerning motion parameters, between 100%, 90%, and 80% Percoll fractions, which can thereby be pooled in case of insufficient sperm recovering in 100% fraction. On the contrary there is some doubt about the fertilizing ability of spermatozoa recovered in 70% and 60% Percoll layers, since VCL, LIN, and especially HA are severely decreased.